Researchers aim to improve on the gold-standard technique for detecting gum disease, which is plagued with error and poor reproducibility.

Although cuttlefish or squid ink pasta is commonly found on the menu at Italian restaurants, a new study shows the food-grade dye could come in handy at the dentist's office as well. Researchers at the University of California, San Diego used ink from cuttlefish—a relative of squids—as a contrast medium for photoacoustic ultrasound imaging of gums. They tested the technique on porcine gum tissue, and have plans to later collaborate with dentists to test the method in humans.

Gingivitis, or inflammation of the gums caused by bacteria, can advance to gum disease if left untreated. The gums pull away from the teeth, forming pockets that become infected. Typically, dentists use a periodontal probe—a long, thin metal pick—to check the depth of pockets. Despite remaining the gold standard for gum examinations, periodontal probes are prone to error and poor reproducibility.

In an attempt to improve on resolution and accuracy, the authors of the paper tested a new, noninvasive approach: photoacoustic imaging with a cuttlefish ink rinse. Photoacoustic imaging uses short laser pulses to heat up tissue, causing it to expand in size, and ultrasonic transducers then measure the resulting pressure waves. The technique successfully imaged dental pockets and offered high precision among different probing depths in 39 porcine teeth. Photoacoustic imaging also covered the entire pocket, as opposed to the probe-based approach, which is limited to only a few sites.

Cuttlefish ink contains melanin nanoparticles, which have broad optical absorption for photoacoustic imaging, and the ink has no safety concerns. The results agreed well with periodontal probe measurements, but with increased reproducibility and precision, and an expanded view of the gums, demonstrating the potential of this modern imaging technique for dental applications.